Premise: To help understand the mechanical effects and benefits of the modifiers that are carried on weapons of Uncommon or higher levels of rarity.

Initial Observations: With the release of Season Four, modifiers on weaponry are doubly useful, providing both their static bonus and increasing the baseline damage output of a given weapon, an increase of 5% per extra modifier (i.e. Uncommon = +5%; Rare = +10%; Very Rare = +15%). With this change, it now becomes of paramount importance to acquire, at the very least, Rare or Very Rare weaponry, to maximize the potential of a build.

There are actually six (thanks, Zorena ) modifiers currently in-game (although one of these, [Rch], only exists on a single weapon, currently, the Rapid-Fire Transphasic Torpedo, which is rewarded from Cold Call in the Breen series of Featured Episodes; the other is a unique class of weapons with the [Borg] modifier, which will be explained in the [Dmg] section); this will discuss the four, primary modifiers.
Now, on to the modifiers...

Accuracy: [Acc]

Bonus: +10% Accuracy for this weapon; does not boost the Accuracy of any other weapon. Stacks with Bonus Accuracy gained from the Accurate trait, or skillpoints spent in the Starship Attack Vectors skill.

Mechanical Application: Primarily important for determining To-Hit Chance (as detailed in this thread), each instance of [Acc] helps to alleviate a high Defense value on an opponent, and grants a bonus to both your Critical Chance and your Critical Severity, if your Accuracy exceeds your target's Defense.

How much value does each instance of [Acc] provide? Simple question, challenging answer.

First, the target that you are shooting at will greatly affect the value of one or more [Acc]'s; this is due to the Accuracy vs. Defense curve, which becomes more sharply-defined, the closer together your Accuracy and your target's Defense become (whether you have very high Accuracy and the target has very low Defense, or vice versa). A Cruiser will 'typically' run in the 50-65% Defense range (depending on things like Engine choice, gear, and Captain traits, specifically, Elusive); a Science Vessel can run anywhere from 50-80% on 'typical' layouts, ship class often contributes greatly to the variation; Escorts typically run in the 70-90% Defense rating.

Second, because of the nature of the Acc vs. Def curve, the value of [Acc] increases, the closer that you bring your Accuracy to their Defense, optimizing your opportunity to hit your target.

Maximum, possible, known (as far as our understanding of the game mechanics go, without having the actual code to examine) bonus Accuracy: +65%, +25% from Attack Vectors, +10% from Accurate Trait, +30% from [Acc]x3 weapon. (There is some speculation (with inconclusive, thus far, test results) that certain weapon-types may have inherently higher base Accuracy, affecting their final total, but, again, this is speculation, without solid proof.)

Quantitative Value Per Modifier: (Note: I considered referring to this as Quantitative Quality, abbreviated as QQ... But, decided against it...) A 'hard' number is strictly based on the situation surrounding each, individual pulse of a given weapon, however, these are some general guidelines (assuming that your target's Defense 'generally' exceeds your potential Accuracy, exceptions will be discussed later):

If your Accuracy Vs. Defense Differential [AVDD, the difference between your Accuracy and your target's Defense rating without any Accuracy-equipped weapons] is from 0-10%, each instance of [Acc] is worth an 8-10% increase in To-Hit Chance (and Overflow, if your Accuracy ends up exceeding their Defense).

If your AVDD is from 10-30%, each instance of [Acc] is worth a 5-7% increase in To-Hit Chance.

If your AVDD is from 30-50%, each instance of [Acc] is worth a 4-5% increase in To-Hit Chance.

If your AVDD is 50%+, each instance of [Acc] is worth about 3% increase in To-Hit Chance.

Value for PvE: Moderate. Most opponents in PvE (with the rare exceptions of the Mogai and the Borg Sphere, both of which use speed-enhancing abilities) will be traveling slowly enough that the inclusion of [Acc]-equipped weapons is not 'as' essential to ensure that a majority of your weapons' fire will hit; however, thanks to the benefits of Accuracy Overflow, it is never a bad addition.

Value for PvP: High to Extreme. Unlike in PvE, most human opponents will be running the fastest, highest-Defense setup that they can field, thus underscoring the importance of boosting your available Accuracy. Every percentage point that you can increase your To-Hit Chance is a corresponding increase in your DPS. If your ship is running a largely 'traditional' setup, this is likely the ideal choice for most of your weaponry, ensuring that you maximize your To-Hit Chance (and, subsequently, your damage output). The great exception to this valuation of [Acc], is a build that uses CC powers to slow or stop its targets, whether through Science powers that disable/immobilize, or things such as Target Subsystem: Engines, a build that can consistently stop or severely slow a target does not nearly rely upon [Acc] as much as other builds; however, even in these cases, thanks to Accuracy Overflow, it remains a viable and useful choice.

Weapon that derives greatest benefit: Beams. With two categories of powers that must hit to be useful (Target Subsystems and Overload), Beams are much more dependent on Accuracy for ensuring that they derive maximum benefit from their BOff powers. If your build includes even a single copy of one of these powers, Accuracy gains substantially greater value for those Beam Weapons. (Fire at Will, with its enormous volume of firepower, does not depend nearly as heavily on Accuracy, scoring its high DPS through weight of fire, rather than highly-accurate fire.)

Conclusion: The most generically 'useful' modifier, you can never go wrong with choosing a weapon that has [Acc] as a modifier. While some weapons might benefit a little more from other modifiers, if you do not have access to such weapons, it is never a bad choice to run an Accurate weapon. Beams, again, if you are running Overloads or Target Subsystems, are much more heavily dependent on [Acc], and should, in most cases, carry Beam Weapons with at least one [Acc] modifier.

Quantitative Value Per Modifier: There are a decent array of skills and powers that can increase your Critical Severity, but this addresses [CrtD] strictly in the absence of other modifiers.

All weapons (excluding DHC's, which gain +10% inherently) have an inherent +50% Critical Severity rating, so each instance of [CrtD] is a 40% increase to the base value.

In the absence of all other modifiers (including, but not limited to things such as: boosted Critical Chance, Critical Severity from other sources, Accuracy, etc.), each instance of [CrtD] boosts your overall, effective DPS by .5%. (Again, assumes no other bonuses, but uses the baseline 2.5% Critical Chance and 70% Critical Severity, 50% base + 20% for [CrtD].)

Value for PvE: Moderate. As most PvE opponents, particularly on higher difficulty levels, have vast reserves of hitpoints, anything that increases the amount of damage that you can deal is appreciated. Not 'quite' as valuable as [CrtH] for PvE purposes, but, still quite useful, especially for the weapon-types detailed below.

Value for PvP: Moderate to High. In PvP, the value of [CrtD] is heavily dependent upon the weapon-type to which it is attached. Best used in conjuction with high-burst weapons (or attack types) to maximize the value of Critical Hits that are scored by those weapons. With the nature of healing and resistances in the current meta-game, at times, a lucky critical can make the difference in ensuring a kill, [CrtD] further enhances the value of those lucky Critical Hits. Additionally, a burst-oriented build that can maximize both the number of shots fired and the likelihood of scoring Critical Hits (usually a Tactical Captain) can derive significant benefit from [CrtD].

Weapon that derives the greatest benefit: Projectiles. Perhaps more clearly than any other weapon/modifier combination, [CrtD] and projectiles are a natural combination. The sole, effective purpose of projectiles is to deliver as large a punch into as tiny a window as possible. Powers and modifiers that enhance or maximize the delivery of burst damage are essential to deriving the greatest benefit from these weapons. A good rule to live by, both when choosing powers and modifiers for your weapons: The less frequently that a weapon or power is available (particularly for burst powers/weapons), the more valuable that [CrtD] becomes, as you will be employing those weapons or powers infrequently, each rare occasion on which you score a Critical Hit, you want it to be for as much damage as possible.

A possible corrolary to this rule would be that Beam Weapons (particularly, Dual Beam Banks) through which you fire Beam: Overloads (if you choose to run these on your build) will likewise benefit from the addition of [CrtD]; however, not to the same degree that [Acc] is necessary.

Conclusion: While not as universally-valuable as [Acc], [CrtD] still has a place of value with burst-heavy weapons or builds (often, both). Again, for projectiles, this is probably the most valuable modifier, and the general rule: The less-frequently that you fire the weapon/power, the more valuable [CrtD] becomes.

Bonus: +2% Critical Chance for this weapon; does not boost the Critical Chance of other equipped Weapons. Stacks with bonus from things like APA or Starship Combat Maneuvers (I think? Cannot remember off-hand which one boost Critical Chance).

Mechanical Application: Raises the chance of scoring a Critical Hit on any other hit by 2%. A weapon must score a normal 'Hit' in order to roll a 'Critical Chance', thus, Accuracy still plays an important role.

Quantitative Value Per Modifier: [CrtH] increases the likelihood that a normal Hit will be turned into a Critical Hit, thus improving your overall DPS.

All weapons, in the absence of other factors, have an inherent 2.5% Critical Chance, thus, each instance of [CrtH] provides an 80% boost to that base value.

For each instance of [CrtH], your overall, effective DPS is increased by 1%.

Value for PvE: High. As concerns for Accuracy are not 'quite' as high as in PvP, boosting your opportunity to score Critical Hits (and the accompanying increase in damage output) will help you to whittle through the barrels of hitpoints that NPC's possess (particularly in STF's or on higher difficulty levels). As detailed below, rapid-firing weapons will gain the most from this modifier.

Value for PvP: High. While weapon type (as explained below) can significantly impact the value of [CrtH], the current meta-game, with powerful stacking of both heals/resistances and a corresponding stacking of damage-boosting abilities, a modifier that increases the chances of scoring Critical Hits can prove quite useful, particularly for weapons that fire frequently, or on a build that can limit a target's Defense rating.

Weapon that derives the greatest benefit: Cannons (including DHC's, DC's, SC's, and Turrets). The functionally-opposite theory of [CrtD] applies to [CrtH], in that the more frequently a weapon fires, the more valuable [CrtH] becomes. Even in the absence of Accuracy concerns, the larger the 'sample size' (a math nerd's term for hitting them as often as you can), the greater number of opportunities to make the Critical Chance rolls, and each instance of [CrtH] dramatically increases the likelihood of scoring those powerful Critical Hits. Take a Captain that has fully-skilled the appropriate Tactical Skill to improve their base Critical Chance to 4.5%, each instance of [CrtH] is still a 44.4% increase to that baseline. Conversely, the less frequently a weapon fires, the less valuable [CrtH] becomes, as your 'sample size' for each, individual combat will limit the benefit of this modifier.

Take a simplistic comparison: In 60 seconds, you will be able to fire a Quantum Torpedo 7.5 times, it will take you two, full minutes to get to the statistical probability of scoring even a single Critical Hit with one instance of [CrtH] (though, not guaranteed, even throwing THY3 into the mix, it will be a full minute before you hit the same, statistical likelihood of a single Critical Hit). On the other hand, take a Dual Heavy Cannon, which, even without Rapid Fire, with one instance of [CrtH], reaches the same, statistical probability of scoring at least one Critical Hit, in less than 25 seconds, with Rapid Fire, it drops to under 15 seconds to reach the level of statistical probability; this statistical effect is amplified by multiplying the number of [CrtH] modifiers or increasing the number of firing weapons (or both).

Conclusion: Again, not 'quite' as universally-valuable as [Acc], [CrtH] very quickly renders a high return on rapid-firing weaponry (especially in conjunction with powers that increase rate-of-fire). Especially powerful in conjunction with builds that can reduce or eliminate a target's Defense rating, as increasing the number of Hits scored will further increase the number of opportunities to roll a Critical Chance.

ask some one that is smarter then you great post with the entry of season 4 ground combat has become mor previlent. I am unaware of an instance but if you have already done this a break down of ground weapon modifiers would be very interesting. thanks for the great post.

I would suggest however that Crit Severity is also quite good on fast firing things like Turrets and Cannons. Why? Because by the sheer number of shots fired they have a higher % chance to land a Crit by virtue of the laws of probability. Therefore, as they are more likely to land critical hits they also will get more DPS out of the bonus damage they receive when hitting critically.

Torpedoes by contrast fire so slowly (aside from Photon) that they have a low probability to actually strike critically and therefore while the increased damage is nice when it happens they are better served by Chance to Crit modifiers that will increase the likelihood that any given hit is a Crit.

Basically what I am saying is this: You want to go with the argument that you should apply the modifier that goes along with the strength of the weapon. I would argue that you want the modifier that covers the weakness of the weapon.

Torpedoes fire very slowly thus lowering their chance of critical strikes or and procs but deal massive damage per projectile.

Thus: Adding a higher amount of damage to the already frequently criting Cannons allows them to make each instance of a Critical more damaging and having a higher critical chance on the Torpedo allows it to use its full yield more frequently.

It is a debatable point however. Just thought I would throw that out for thought.